Utilities must by law purchase a third of their electricity from solar, wind, or other renewable sources by 2020, and state policy encourages utilities to buy from in-state projects. The Tehachapi wind project north of Los Angeles added 720 megawatts to the electric grid this year, much of it sold to Southern California Edison. San Diego Gas & Electric Co. signed a deal to
buy 189 megawatts of wind power
from the same area in February 2012.